There’s a much simpler solution. Ditch the whole “Mission Identifier” deal, it’s obsolete. or at least stop worrying about getting it right when so many airframes can do so many things.
It made sense when air forces were fielding dozens of types, with many types occupying the same, or similar role. now, the USAF has a couple of anti air fighters (F-22, F-15), a couple of air-ground fighters (F-16, F-15E), 3 bombers (b-52, B-1, B2), and a CAS plane (A-10). and that’s about it for fast jets.
The second point is that, while an airframe may be capable of performing multiple missions, the squadrons tend to specialise — there’s unlikely ever to be enough training time for a squadron to cover every possible role their multi-role airframes can handle. So, it makes far more sense to simply number or name the airframe designs, and then worry about specific mission identifiers for squadrons.